SAR Prediction and SAR Management for Parallel Transmit MRI

SAR Prediction and SAR Management for Parallel Transmit MRI PDF Author: Hanno Homann
Publisher: KIT Scientific Publishing
ISBN: 3866448007
Category : Technology & Engineering
Languages : en
Pages : 146

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Book Description
Parallel transmission enables control of the RF field in high-field Magnetic Resonance Imaging (MRI). However, the approach has also caused concerns about the specific absorption rate (SAR) in the patient body. The present work provides new concepts for SAR prediction. A novel approach for generating human body models is proposed, based on a water-fat separated MRI pre-scan. Furthermore, this work explores various approaches for SAR reduction.

SAR Prediction and SAR Management for Parallel Transmit MRI

SAR Prediction and SAR Management for Parallel Transmit MRI PDF Author: Hanno Homann
Publisher: KIT Scientific Publishing
ISBN: 3866448007
Category : Technology & Engineering
Languages : en
Pages : 146

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Book Description
Parallel transmission enables control of the RF field in high-field Magnetic Resonance Imaging (MRI). However, the approach has also caused concerns about the specific absorption rate (SAR) in the patient body. The present work provides new concepts for SAR prediction. A novel approach for generating human body models is proposed, based on a water-fat separated MRI pre-scan. Furthermore, this work explores various approaches for SAR reduction.

Effects of Wetland Conversion to Farming on Water Quality and Sediment and Nutrient Retention in a Tropical Catchment

Effects of Wetland Conversion to Farming on Water Quality and Sediment and Nutrient Retention in a Tropical Catchment PDF Author: Abias Uwimana
Publisher: CRC Press
ISBN: 9781000025606
Category : Science
Languages : en
Pages : 0

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Book Description
The study used a combination of landscape-scale synoptic surveys (catchment, reaches) and mesocosm surveys (experimental plots) to assess the impacts of conversion of natural valley-bottom wetlands to farming land on the water quality and retention of sediment and nutrients. The results showed that temperature, pH, electrical conductivity and dissolved oxygen concentration decreased, and total suspended solids (TSS) increased with storm water increase. Nitrogen (TN) and phosphorus (TP) accumulated in the catchment during the dry season and washed into the water courses during the early stages of the higher flows, with subsequent lower concentrations at the end of the rains due to dilution. Large proportions of the annual loads of TSS, TP and TN (93%, 60% and 67%, respectively) were transported during rainfall events that occurred in 115 days. Fishponds acted as temporal traps of TSS, TN and TP at the early stages of farming, and were a source of and TN and TP at the end of the farming period, in contrast to rice farming that generated sediments and nutrients early in the farming period and trapped them at the end of the farming season. Wetlands mostly acted as sinks but sometimes as a source of sediment and nutrients.

Brain and Human Body Modeling

Brain and Human Body Modeling PDF Author: Sergey Makarov
Publisher: Springer Nature
ISBN: 3030212939
Category : Technology & Engineering
Languages : en
Pages : 398

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Book Description
This open access book describes modern applications of computational human modeling with specific emphasis in the areas of neurology and neuroelectromagnetics, depression and cancer treatments, radio-frequency studies and wireless communications. Special consideration is also given to the use of human modeling to the computational assessment of relevant regulatory and safety requirements. Readers working on applications that may expose human subjects to electromagnetic radiation will benefit from this book’s coverage of the latest developments in computational modelling and human phantom development to assess a given technology’s safety and efficacy in a timely manner. Describes construction and application of computational human models including anatomically detailed and subject specific models; Explains new practices in computational human modeling for neuroelectromagnetics, electromagnetic safety, and exposure evaluations; Includes a survey of modern applications for which computational human models are critical; Describes cellular-level interactions between the human body and electromagnetic fields.

ECG Imaging of Ventricular Activity in Clinical Applications

ECG Imaging of Ventricular Activity in Clinical Applications PDF Author: Schulze, Walther H. W.
Publisher: KIT Scientific Publishing
ISBN: 3731503743
Category : Technology (General)
Languages : en
Pages : 238

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Book Description
ECG imaging was performed in humans to reconstruct ventricular activation patterns and localize their excitation origins. The precision of the non-invasive reconstructions was evaluated against invasive measurements and found to be in line with the state-of-the-art literature. Statistics were produced for various excitation origins and reveal the beat-to-beat robustness of the imaging method.

Modeling Human Atrial Patho-Electrophysiology from Ion Channels to ECG - Substrates, Pharmacology, Vulnerability, and P-Waves

Modeling Human Atrial Patho-Electrophysiology from Ion Channels to ECG - Substrates, Pharmacology, Vulnerability, and P-Waves PDF Author: Loewe, Axel
Publisher: KIT Scientific Publishing
ISBN: 3731505282
Category : Technology (General)
Languages : en
Pages : 342

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Book Description
Half of the patients suffering from atrial fibrillation (AF) cannot be treated adequately, today. This book presents multi-scale computational methods to advance our understanding of patho-mechanisms, to improve the diagnosis of patients harboring an arrhythmogenic substrate, and to tailor therapy. The modeling pipeline ranges from ion channels on the subcellular level up to the ECG on the body surface. The tailored therapeutic approaches carry the potential to reduce the burden of AF.

Personalized Multi-Scale Modeling of the Atria: Heterogeneities, Fiber Architecture, Hemodialysis and Ablation Therapy

Personalized Multi-Scale Modeling of the Atria: Heterogeneities, Fiber Architecture, Hemodialysis and Ablation Therapy PDF Author: Martin Wolfgang Krüger
Publisher: KIT Scientific Publishing
ISBN: 3866449488
Category : Technology & Engineering
Languages : en
Pages : 320

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Book Description
This book targets three fields of computational multi-scale cardiac modeling. First, advanced models of the cellular atrial electrophysiology and fiber orientation are introduced. Second, novel methods to create patient-specific models of the atria are described. Third, applications of personalized models in basic research and clinical practice are presented. The results mark an important step towards the patient-specific model-based atrial fibrillation diagnosis, understanding and treatment.

Multiscale Modeling of Cardiac Electrophysiology: Adaptation to Atrial and Ventricular Rhythm Disorders and Pharmacological Treatment

Multiscale Modeling of Cardiac Electrophysiology: Adaptation to Atrial and Ventricular Rhythm Disorders and Pharmacological Treatment PDF Author: Mathias Wilhelms
Publisher: KIT Scientific Publishing
ISBN: 3731500450
Category : Technology & Engineering
Languages : en
Pages : 206

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Book Description
Multiscale modeling of cardiac electrophysiology helps to better understand the underlying mechanisms of atrial fibrillation, acute cardiac ischemia and pharmacological treatment. For this purpose, measurement data reflecting these conditions have to be integrated into models of cardiac electrophysiology. Several methods for this model adaptation are introduced in this thesis. The resulting effects are investigated in multiscale simulations ranging from the ion channel up to the body surface.AbstractEnglisch = Multiscale modeling of cardiac electrophysiology helps to better understand the underlying mechanisms of atrial fibrillation, acute cardiac ischemia and pharmacological treatment. For this purpose, measurement data reflecting these conditions have to be integrated into models of cardiac electrophysiology. Several methods for this model adaptation are introduced in this thesis. The resulting effects are investigated in multiscale simulations ranging from the ion channel up to the body surface.

ECG Based Analysis of the Ventricular Repolarisation in the Human Heart

ECG Based Analysis of the Ventricular Repolarisation in the Human Heart PDF Author: Baas, Tobias
Publisher: KIT Scientific Publishing
ISBN: 3866448821
Category : Technology & Engineering
Languages : en
Pages : 260

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Book Description
ECG recordings provide diagnostic relevant information on the de- and repolarisation sequences of the heart. A modification of the repolarisation sequence is assumed to cause Torsades de Pointes. Especially drug induced effects on the repolarisation processes are in focus, since some non-cardiac drugs have been associated with sudden cardiac death in the 1990s.The analysis of the ventricular repolarisation using a set of parameters depicting the morphology of the T-wave is introduced in this work. Therefore, new methods of fully automatic patient-specific QRS detection, beat classification and precise T-wave delineation are presented. Using these methods, medical studies are investigated regarding the modification of the T-wave by different compounds. Also the impact of the heart rate on the morphology of the T-wave is part of this research.The reliable identification of ventricular ectopic beats allows an analysis of the influence of these beats on subsequent heart beats. It turned out that the morphology of subsequent heart beats can significantly be changed. This might give new information on the proarrythmical risk of ventricular ectopic beats.

Formation of Intracardiac Electrograms under Physiological and Pathological Conditions

Formation of Intracardiac Electrograms under Physiological and Pathological Conditions PDF Author: Keller, Matthias
Publisher: KIT Scientific Publishing
ISBN: 3731502283
Category : Technology & Engineering
Languages : en
Pages : 264

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Book Description
This work presents methods to advance electrophysiological simulations of intracardiac electrograms (IEGM). An experimental setup is introduced, which combines electrical measurements of extracellular potentials with a method for optical acquisition of the transmembrane voltage in-vitro. Thereby, intracardiac electrograms can be recorded under defined conditions. Using experimental and clinical signals, detailed simulations of IEGMs are parametrized, which can support clinical diagnosis.

Analysis of Atrial Electrograms

Analysis of Atrial Electrograms PDF Author: Christopher Schilling
Publisher: KIT Scientific Publishing
ISBN: 3866448945
Category : Atrial fibrillation
Languages : en
Pages : 240

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Book Description
This work provides methods to measure and analyze features of atrial electrograms - especially complex fractionated atrial electrograms (CFAEs) - mathematically. Automated classification of CFAEs into clinical meaningful classes is applied and the newly gained electrogram information is visualized on patient specific 3D models of the atria. Clinical applications of the presented methods showed that quantitative measures of CFAEs reveal beneficial information about the underlying arrhythmia.